Duct system for a refrigerator appliance

ABSTRACT

A duct system for a refrigerator appliance is provided. A fresh food supply duct provides fluid communication between an evaporator chamber and a fresh food chamber. A convertible chamber supply and return duct each provide fluid communication between the evaporator chamber and a convertible chamber. A dual damper is operably coupled to the convertible chamber supply and return duct for selectively and simultaneously opening or closing the convertible chamber supply duct and the convertible chamber return duct.

FIELD OF THE INVENTION

The present subject matter relates generally to refrigerator appliances, and more particularly, to refrigerator appliances having improved refrigeration and air flow duct systems.

BACKGROUND OF THE INVENTION

Certain refrigerator appliances utilize sealed systems for cooling chilled chambers of the refrigerator appliances. A typical sealed system includes an evaporator and a fan, the fan generating a flow of air across the evaporator and cooling the flow of air. The cooled air is then provided through an opening into the chilled chamber to maintain the chilled chamber at a desired temperature. Air from the chilled chamber is circulated back through a return duct to be re-cooled by the sealed system during operation of the refrigerator appliance, maintaining the chilled chamber at the desired temperature.

Certain refrigerators appliances also include multiple fresh food and/or freezer compartments configured for maintaining different temperatures for storing different types of food and drink. For example, a conventional bottom mount refrigerator has a fresh food chamber positioned above a freezer chamber. In addition, such a refrigerator may further include a convertible chamber positioned between the fresh food chamber and the freezer chamber. The convertible chamber, for example, may be adjusted between a conventional freezer chamber temperature and a fresh food chamber temperature (e.g., between 0° F. and 41° F.).

However, achieving different temperatures in each of the chambers of such refrigerator appliances typically requires a separate evaporator for each chamber. In this regard, a single compressor may drive refrigerant through a switching mechanism to an evaporator configured for cooling a single chamber at a time. However, additional evaporators result in added costs, more complicated assembly, and a more complex refrigerant plumbing configuration. In addition, complicated switching mechanisms may be required or operational limitations may arise, e.g., only a single chamber may be cooled at a single time due to the shared compressor.

Accordingly, a refrigerator appliance including multiple chambers sharing an improved refrigeration and duct system would be useful. More particularly, a refrigeration system that can provide cooling air flow from a single evaporator to multiple chambers in desired proportions would be especially beneficial.

BRIEF DESCRIPTION OF THE INVENTION

The present subject matter provides a duct system for a refrigerator appliance. A fresh food supply duct provides fluid communication between an evaporator chamber and a fresh food chamber. A convertible chamber supply and return duct each provide fluid communication between the evaporator chamber and a convertible chamber. A dual damper is operably coupled to the convertible chamber supply and return duct for selectively and simultaneously opening or closing the convertible chamber supply duct and the convertible chamber return duct. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In a first exemplary embodiment, a refrigerator appliance is provided. The refrigerator appliance defines a vertical direction, a lateral direction, and a transverse direction, the vertical, lateral, and transverse directions being mutually perpendicular. The refrigerator appliance includes a cabinet including an inner liner defining a fresh food chamber, a convertible chamber, and a freezer chamber. An evaporator is positioned within an evaporator chamber, the evaporator configured for cooling air in the evaporator chamber. A fresh food supply duct provides fluid communication between the evaporator chamber and the fresh food chamber, a convertible chamber supply duct provides fluid communication between the evaporator chamber and the convertible chamber, and a convertible chamber return duct provides fluid communication between the convertible chamber and the evaporator chamber. A dual damper is operably coupled to the convertible chamber supply duct and the convertible chamber return duct, the dual damper being configured for simultaneously and selectively opening or closing the convertible chamber supply duct and the convertible chamber return duct.

According to another exemplary embodiment, a duct system for a refrigerator appliance is provided. The refrigerator appliance includes a cabinet containing an inner liner defining a fresh food chamber, a convertible chamber, a freezer chamber, and an evaporator chamber. The duct system includes a fresh food supply duct providing fluid communication between the evaporator chamber and the fresh food chamber, a convertible chamber supply duct providing fluid communication between the evaporator chamber and the convertible chamber, and a convertible chamber return duct providing fluid communication between the convertible chamber and the evaporator chamber. A dual damper is operably coupled to the convertible chamber supply duct and the convertible chamber return duct, the dual damper being configured for selectively and simultaneously opening or closing the convertible chamber supply duct and the convertible chamber return duct.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a front view of a refrigerator appliance according to an exemplary embodiment of the present subject matter.

FIG. 2 provides a schematic view of a sealed cooling system configured for cooling the exemplary refrigerator appliance of FIG. 1 according to an exemplary embodiment of the present subject matter.

FIG. 3 provides a schematic front view of the exemplary refrigerator appliance of FIG. 1 according to an exemplary embodiment of the present subject matter.

FIG. 4 provides a schematic side view of the exemplary refrigerator appliance of FIG. 1 according to an exemplary embodiment of the present subject matter.

FIG. 5 provides a schematic rear view of the exemplary refrigerator appliance of FIG. 1 according to an exemplary embodiment of the present subject matter.

FIG. 6 provides a schematic view of a flow restriction or trap that may be defined by a fresh food supply duct of the exemplary refrigerator appliance of FIG. 1 according to an exemplary embodiment.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

FIG. 1 provides a front view of a refrigerator appliance 100 according to an exemplary embodiment of the present subject matter. Refrigerator appliance 100 includes a cabinet or housing 102 that extends between a top 104 and a bottom 106 along a vertical direction V, between a first side 108 and a second side 110 along a lateral direction L, and between a front side 112 and a rear side 114 (FIG. 4) along a transverse direction T (FIG. 4). Each of the vertical direction V, lateral direction L, and transverse direction T are mutually perpendicular to one another.

Housing 102 defines chilled chambers for receipt of food items for storage. In particular, housing 102 defines a fresh food chamber 122 positioned at or adjacent top 104 of housing 102, a freezer chamber 124 arranged at or adjacent bottom 106 of housing 102, and a convertible chamber 126 positioned between the fresh food chamber 122 and the freezer chamber 124 along the vertical direction V. As such, refrigerator appliance 100 is generally referred to as a bottom mount refrigerator. It is recognized, however, that the benefits of the present disclosure apply to other types and styles of refrigerator appliances such as, e.g., a top mount refrigerator appliance or a side-by-side style refrigerator appliance. Consequently, the description set forth herein is for illustrative purposes only and is not intended to be limiting in any aspect to any particular refrigerator chamber configuration.

Refrigerator doors 128 are rotatably hinged to an edge of housing 102 for selectively accessing fresh food chamber 122. In addition, freezer doors 130 are arranged below refrigerator doors 128 for selectively accessing freezer chamber 124 and convertible chamber 126. Freezer doors 130 are coupled to freezer drawers (not shown) that are slidably mounted within freezer chamber 124 and convertible chamber 126. To prevent leakage of cool air, refrigerator doors 128, freezer doors 130, and/or housing 102 may define one or more sealing mechanisms (e.g., rubber gaskets, not shown) at the interface where the doors 128, 130 meet housing 102. It should be appreciated that doors having a different style, position, or configuration are possible and within the scope of the present subject matter.

FIG. 1 provides a front view of refrigerator appliance 100 with refrigerator doors 128 and freezer doors 130 shown in an open position. According to the illustrated embodiment, various storage components are mounted within fresh food chamber 122, freezer chamber 124, and convertible chamber 126 to facilitate storage of food items therein as will be understood by those skilled in the art. In particular, the storage components include bins 132, drawers 134, and shelves 136 that are mounted within fresh food chamber 122 or freezer chamber 124. Bins 132, drawers 134, and shelves 136 are configured for receipt of food items (e.g., beverages and/or solid food items) and may assist with organizing such food items. As an example, drawers 134 can receive fresh food items (e.g., vegetables, fruits, and/or cheeses) and increase the useful life of such fresh food items.

Refrigerator appliance 100 further includes a controller 140. Operation of the refrigerator appliance 100 is regulated by controller 140 that is operatively coupled to a control panel (not shown). In one exemplary embodiment, the control panel may represent a general purpose I/O (“GPIO”) device or functional block. In another exemplary embodiment, the control panel may include input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, touch pads, and touch screens. The control panel may be in communication with controller 140 via one or more signal lines or shared communication busses. The control panel provides selections for user manipulation of the operation of refrigerator appliance 100. In response to user manipulation of the control panel, controller 140 operates various components of refrigerator appliance 100. For example, controller 140 is operatively coupled or in communication with various components of a sealed system, as discussed below. Controller 140 may also be in communication with a variety of sensors, such as, for example, chamber temperature sensors or damper position sensors. Controller 140 may receive signals from these temperature sensors that correspond to the temperature of an atmosphere or a position of a damper or damper assembly.

Controller 140 includes memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of refrigerator appliance 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, controller 140 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

Referring now to FIG. 2, a schematic view of an exemplary sealed system 150 which may be used to cool fresh food chamber 122, freezer chamber 124, and convertible chamber 126 will be described. Sealed system 150 is generally configured for executing a vapor compression cycle for cooling air within refrigerator appliance 100, e.g., within fresh food chamber 122 and freezer chamber 124. Sealed cooling system 150 includes a compressor 152, a condenser 154, an expansion device 156, and an evaporator 158 connected in series and charged with a refrigerant.

During operation of sealed system 150, gaseous refrigerant flows into compressor 152, which operates to increase the pressure of the refrigerant. This compression of the refrigerant raises its temperature, which is lowered by passing the gaseous refrigerant through condenser 154. Within condenser 154, heat exchange with ambient air takes place so as to cool the refrigerant and cause the refrigerant to condense to a liquid state.

Expansion device (e.g., a valve, capillary tube, or other restriction device) 156 receives liquid refrigerant from condenser 154. From expansion device 156, the liquid refrigerant enters evaporator 158. Upon exiting expansion device 156 and entering evaporator 158, the liquid refrigerant drops in pressure and vaporizes. Due to the pressure drop and phase change of the refrigerant, evaporator 158 is cool relative to chambers 122, 124, 126 of refrigerator appliance 100. As such, cooled air is produced and refrigerates chambers 122, 124, 126 of refrigerator appliance 100. Thus, evaporator 158 is a type of heat exchanger which transfers heat from air passing over evaporator 158 to refrigerant flowing through evaporator 158.

It should be appreciated that the illustrated sealed system 150 is only one exemplary configuration of sealed system 150 which may include additional components, e.g., one or more additional evaporators, compressors, expansion devices, and/or condensers. As an example, sealed cooling system 150 may include two evaporators. As a further example, sealed system 150 may further include an accumulator 160. Accumulator 160 may be positioned downstream of evaporator 158 and may be configured to collect condensed refrigerant from the refrigerant stream prior to passing it to compressor 152.

Referring now generally to FIGS. 3 through 5, cabinet or housing 102 includes an inner liner 172 which defines chambers 122, 124, and 126. For example, inner liner 172 may be an injection-molded liner attached to an inside of housing 102. Insulation 174, such as expandable foam can be present between housing 102 and inner liner 172 in order to assist with insulating chambers 122, 124, and 126. For example, sprayed polyurethane foam may be injected into a cavity defined between housing 102 and inner liner 172 after they are assembled. Refrigerator doors 128 and freezer doors 130 may be constructed in a similar manner to assist in insulating chambers 122, 124, and 126.

According to the exemplary illustrated embodiment of FIG. 3, inner liner 172 may define a back wall 176 that extends between top 104 and bottom 106 of refrigerator appliance 100 along the vertical direction V. In addition, refrigerator appliance 100 further includes fixed or removable mullions 178 positioned within housing 102 to define fresh food chamber 122, freezer chamber 124, and convertible chamber 126. More specifically, according to the illustrated embodiment, mullions 178 generally extend between a chamber opening and back wall 176 along the transverse direction T and between first side 108 and a second side 110 along the lateral direction L. In this manner, mullions 178 are generally horizontally-oriented and split refrigerator appliance into chambers 122, 124, and 126. As illustrated, fresh food chamber 122, freezer chamber 124, and convertible chamber 126 are vertically stacked such that fresh food chamber 122 is positioned above convertible chamber 126 along the vertical direction V and convertible chamber 126 is positioned above freezer chamber 124 along the vertical direction V. However, it should be appreciated that aspects of the present subject matter may apply to refrigerator appliances having any number, size, and configuration of cooling chambers.

To limit heat transfer between fresh food chamber 122, freezer chamber 124, and convertible chamber 126, mullions 178 may generally be formed from an insulating material such as foam. In addition, to provide structural support, a rigid injection molded liner or a metal frame may surround the insulating foam. According to another exemplary embodiment, each mullion 178 may be a vacuum insulated panel or may contain a vacuum insulated panel to minimize heat transfer between fresh food chamber 122, freezer chamber 124, and convertible chamber 126. According to an exemplary embodiment, inner liner 172 and/or mullion 178 may include features such as guides or slides, e.g., to ensure proper positioning, installation, and sealing of mullion 178 within inner liner 172.

A seal, such as a rubber or foam gasket (not shown), may be positioned around a perimeter of mullions 178 where they contact inner liner 172, refrigerator doors 128, and/or freezer doors 130. In addition, mullions 178 can be formed to have the same shape as inner liner 172 such that a tight seal is formed when mullion 178 is installed. According to the exemplary embodiment, mullions 178 may be removable such that inner liner 172 may be formed in the same shape as conventional single compartment refrigerator chamber. In this manner, the same tooling may be used to form both refrigerator appliances, thereby reducing costs. In addition, mullions 178 may be removable to facilitate repair and/or maintenance of refrigerator appliance 100. For example, lower mullion 178 is removable to facilitate repair or replacement of a damper or a damper assembly. It should be appreciated that mullions 178 may be sized, positioned, and configured in any suitable manner to form separate chambers within refrigerator appliance 100.

Referring again generally to FIGS. 3 through 5, evaporator 158 is positioned adjacent back wall 176 of inner liner 172. An evaporator cover 180 is positioned over evaporator 158 to define an evaporator chamber 182 with inner liner 172. For example, as illustrated, evaporator cover 180 is positioned within freezer chamber 124 over evaporator 158 such that inner liner 172, mullion 178, and evaporator cover 180 define evaporator chamber 182 which houses evaporator 158.

In addition, evaporator cover 180 and inner liner 172 may define various fluid inlets or supply ports and outlets or return ports for allowing air to circulate through evaporator chamber 182. More specifically, as illustrated, evaporator cover 180 and inner liner 172 define one or more inlets 184 proximate a suction side or suction plenum 186 of evaporator chamber 182. In addition, evaporator cover 180 and inner liner 172 define one or more outlets 188 proximate a discharge plenum 190 of evaporator chamber 182. In operation, relatively warm return air enters suction plenum 186 of evaporator chamber 182 through inlets 184. The air is cooled as it is drawn through evaporator 158 toward discharge plenum 190 where it is distributed through outlets 188 to various supply ducts.

Notably, according to the illustrated embodiment, inlets 184 are positioned below evaporator 158 along the vertical direction V. For example, inlets 184 may be positioned substantially proximate a bottom of freezer chamber 124 (e.g., proximate bottom wall 106 of refrigerator appliance 100). It should be appreciated, that as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error. In this manner, return air is routed below evaporator 158 to promote the cooling and dehydration of the air as it passes through the evaporator coils. It should be appreciated, however, that according to alternative embodiments, any other suitable means for providing fluid communication between evaporator chamber 182 and the various chambers 122, 124, and 126 are possible and within the scope of the present subject matter.

As explained above, sealed cooling system 150 generally operates by circulating air through evaporator chamber 182 to fresh food chamber 122, freezer chamber 124, and convertible chamber 126 of refrigerator appliance 100. Therefore refrigerator appliance 100 generally includes a duct system 200 including one or more return ducts, supply ducts, dampers, fans, and other components to facilitate the movement of cooling air to and from fresh food chamber 122, freezer chamber 124, and convertible chamber 126.

Referring now specifically to FIGS. 3 through 5, duct system 200 generally includes a fresh food supply duct 202 that provides fluid communication between evaporator chamber 182 and fresh food chamber 122. More specifically, fresh food supply duct 202 extends between outlet 188 of discharge plenum 190 and a fresh food chamber supply port 204 substantially along the vertical direction V. According to the illustrated embodiment, fresh food chamber supply port 204 is positioned substantially proximate top 104 of cabinet 102 for supplying cooling air into fresh food chamber 122.

Duct system 200 further includes a convertible chamber supply duct 210 that provides fluid communication between evaporator chamber 182 and convertible chamber 126. More specifically, convertible chamber supply duct 210 extends between outlet 188 of discharge plenum 190 and a convertible chamber supply port 212 substantially along the vertical direction V. According to the illustrated embodiment, convertible chamber supply port 212 is positioned substantially proximate top of convertible chamber for supplying cooling air into convertible chamber 126. As illustrated, convertible chamber supply duct 210 is coupled to fresh food supply duct 202 in a Y-configuration. However, according to alternative embodiments, convertible chamber supply duct 210 could instead be directly coupled to the same or another outlet 188 of discharge plenum 190.

To recirculate air supplied to the various chambers 122, 124, 126 of refrigerator appliance 100, duct system 200 further includes various return ducts as described briefly above. More specifically, duct system 200 includes a convertible chamber return duct 220 providing fluid communication between convertible chamber 126 and evaporator chamber 182. More specifically, convertible chamber return duct 220 extends between a convertible chamber return port 222 positioned on back wall 176 proximate a bottom of convertible chamber 126 and an inlet 184 of evaporator chamber 182. Similarly, duct system 200 includes a first fresh food return duct 224 and a second fresh food return duct 226 positioned on opposite sides of fresh food chamber 122 along the lateral direction L. First fresh food return duct 224 and second fresh food return duct 226 extend between fresh food chamber 122 and inlet 184 proximate suction side 186 of evaporator chamber 182 substantially along the vertical direction V.

According to the illustrated embodiment, fresh food supply duct 202, fresh food return ducts 224, 226, convertible chamber supply duct 210, and convertible chamber return duct 220 are all positioned between inner liner 172 and a rear side 114 of cabinet 102. In this manner, for example, these ducts are foamed in place and surrounded by foamed insulation 174. This allows duct system 200 to be retrofitted into existing refrigerator appliances without reconfiguring the internal space or generating costly new molds for injection molding a new inner liner.

Notably, in very humid environments, thermal energy losses may occur from the various ducts in duct system 200, e.g., due to less insulation 174. More specifically, for example, because duct system 200 is positioned close to rear side 114 of cabinet 102, heat may be lost to the outside and condensation may form on cabinet 102. Therefore, according to an exemplary embodiment of the present subject matter, duct system 200 may further include a vacuum insulated panel 230 positioned adjacent rear side 114 of cabinet 102 to provide additional insulation. For example, vacuum insulated panel 230 may be positioned on an opposite side of fresh food supply duct 202, convertible chamber supply duct 210, and convertible chamber return duct 220 relative to inner liner 172.

Duct system 200 further includes one or more fans to assist in circulating air through evaporator chamber 182 and to refrigerator chambers 122, 124, and 126. For example, according to the illustrated exemplary embodiment, refrigerator appliance 100 includes a fresh food fan 240, a convertible chamber fan 242, and a freezer fan 244, for urging a flow of cooled air from evaporator chamber 182 into fresh food chamber 122, convertible chamber 126, and freezer chamber 124, respectively. According to the illustrated embodiment, fresh food fan 240, convertible chamber fan 242, and freezer fan 244 are each axial fans positioned within respective inlets to each chamber and configured for urging air through evaporator chamber 182. However, it should be appreciated that fans 240, 242, 244 may be any suitable type, size, and configuration for circulating air through evaporator chamber 182. In addition, exemplary embodiments may use fewer than three fans. For example, a single centrifugal fan could be configured for urging a flow of cooling airflow through evaporator chamber 182 and a system of dampers or other flow regulators could be used to selectively direct the flow of cooling air.

Duct system 200 may further include a dual damper 250 operably coupled to convertible chamber supply duct 210 and convertible chamber return duct 220 for controlling the flow of air into and out of convertible chamber 126. More specifically, dual damper 250 is configured for simultaneously and selectively opening or closing convertible chamber supply duct 210 and convertible chamber return duct 220. In this regard, for example, convertible chamber supply port 212 and convertible chamber return port 222 are positioned adjacent each other along the lateral direction L and are separated by a septum or divider wall. Dual damper 250 comprises a single damper flap 252 (FIG. 5) that moves between an open position to allow air to circulate in convertible chamber 126 and a closed position to prevent air from circulating in convertible chamber 126. According to alternative embodiments, damper flap 252 may also be positionable at any intermediate position between the first position and the second position to selectively throttle the amount of airflow circulating through convertible chamber 126.

Dual damper 250 is operated using a drive mechanism such as a single drive motor 254 or any other device suitable for opening and closing damper flap 252. For example, according to the illustrated embodiment, drive motor 254 is a stepper motor controlled by appliance controller 140. However, it should be appreciated that drive motor 254 may have a dedicated controller according to alternative embodiments. It should also be appreciated that drive motor 254 may be an AC or DC motor having any suitable type or configuration. Moreover, the drive mechanism could also be a solenoid with a rotary cam for binary opening (open/close) motion. Likewise, it could be any other means of driving a rotary damper known to those skilled in the art.

In addition, dual damper 250 may include one or more position sensors for determining the angular position of damper flap 252. For example, according to an exemplary embodiment, dual damper 250 includes a Hall-effect sensor configured for sensing a magnetic portion of damper flap 252. In this regard, for example, drive motor 254 may determine the position of damper flap 252 by detecting the presence or absence of the magnet. Alternatively, any other suitable sensors or methods of detecting the position of damper flap 252 may be used.

In addition, according to exemplary embodiments, dual damper 250 may further include one or more heaters for preventing ice from forming on dual damper 250 or melting ice after it forms. For example, a heater could be positioned on damper flap 252 proximate to where it contacts convertible chamber supply port 212 and convertible chamber return port 222. The heater could be operated intermittently to reduce ice build-up or may be operated when drive motor 254 detects that the movement of damper flap 252 is restricted.

As illustrated in FIGS. 3 through 5, fresh food fan 240 urges cooled air from evaporator chamber 182 into fresh food chamber 122. However, because fresh food supply duct 202 does not contain a damper, cool air from freezer chamber 124 and evaporator chamber 182 may have a tendency to migrate through fresh food supply duct 202 into fresh food chamber 122. In addition, cool air may have a tendency to migrate into convertible chamber 126 when dual damper 150 is opened with convertible chamber fan 242 off or in embodiments without dampers. In this regard, for example, duct system 200 could function without dampers as long as the natural convection between convertible chamber 126 and evaporator chamber 182 could be minimized, e.g., by employing traps as described herein.

Notably, as illustrated, a flow restriction, such as a baffle 260, may be positioned within fresh food supply duct 202 to increase flow resistance and minimize undesired flow of cooling air into fresh food chamber 122. Baffle 260 may be sized, positioned, and oriented to balance the flow of cooling air as needed during normal operation and prevent excessive flow of cooling air from evaporator chamber 182 when not desired.

According to the illustrated embodiment, the flow restriction in fresh food supply duct 202 is a single baffle 260 extending from one wall in the direction of cooling air flow. This and other restrictions could allow the removal of some or all dampers within duct system 200 provided that the natural air exchange between evaporator chamber 182 and convertible compartment 126 could be limited by the restriction to allow the achievement of the elevated temperature setting without the addition of heat to convertible compartment 126. However, it should be appreciated that any suitable method of restricting flow may be used according to alternative embodiments. For example, referring briefly to FIG. 6, the size of fresh food supply duct 202 may be decreased to increase flow resistance, a bend or a trap 262 may be formed to reduce the likelihood of undesirable air flow, or a dedicated damper could be used to control the flow of air. Other configurations are possible and within the scope of the present subject matter.

According to the illustrated embodiment, evaporator chamber 182 and evaporator 158 are positioned within freezer chamber 124 of refrigerator appliance 100. In addition, duct system 200 is positioned primarily behind convertible chamber 126 of refrigerator appliance 100. However, it should be appreciated that according to alternative embodiments, evaporator chamber 182 and duct system 200 may be positioned in any suitable location within refrigerator appliance 100. For example, evaporator 158 and duct system 200 could alternatively be positioned entirely within a dedicated chamber within refrigerator appliance 100, e.g., in the mechanical compartment, and may pass cooled air to various chambers through separate ducts or conduits.

Using the features described above, refrigerator appliance 100 is able to maintain fresh food chamber 122 at a fixed, relatively high temperature (e.g., around 37° F. to 41° F.). In addition, refrigerator appliance 100 is able to maintain freezer chamber 124 at a fixed, relatively low temperature (e.g., around 0° F.) while allowing convertible chamber 126 to be selectively adjusted anywhere between the freezer temperature and the fresh food chamber temperature (e.g., between around 0° F. and 41° F.) or higher. In this manner, flexible operation of convertible compartment 126 may be achieved without requiring a dedicated heater for facilitating higher temperatures within convertible compartment 126.

As one skilled in the art will appreciate, the above described embodiments are used only for the purpose of explanation. Modifications and variations may be applied, other configurations may be used, and the resulting configurations may remain within the scope of the invention. For example, evaporator 158 may have different positions or configurations, duct system 200 may be modified, air supply and return ducts may be moved or may have different shapes, and different sealed system configurations may be used. Such modifications and variations are considered to be within the scope of the present subject matter.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A refrigerator appliance defining a vertical direction, a lateral direction, and a transverse direction, the vertical, lateral, and transverse directions being mutually perpendicular, the refrigerator appliance comprising: a cabinet comprising an inner liner defining a fresh food chamber, a convertible chamber, and a freezer chamber; an evaporator positioned within an evaporator chamber, the evaporator configured for cooling air in the evaporator chamber; a fresh food supply duct providing fluid communication between the evaporator chamber and the fresh food chamber; a convertible chamber supply duct providing fluid communication between the evaporator chamber and the convertible chamber; a convertible chamber return duct providing fluid communication between the convertible chamber and the evaporator chamber; and a dual damper operably coupled to the convertible chamber supply duct and the convertible chamber return duct, the dual damper being configured for simultaneously and selectively opening or closing the convertible chamber supply duct and the convertible chamber return duct.
 2. The refrigerator appliance of claim 1, further comprising: a freezer fan for urging a flow of cooled air from the evaporator chamber into the freezer chamber; a convertible chamber fan for urging a flow of cooled air from the evaporator chamber into the convertible chamber when the dual damper is open; and a fresh food fan for urging a flow of cooled air from the evaporator chamber into the fresh food chamber.
 3. The refrigerator appliance of claim 2, wherein the freezer fan, the convertible chamber fan, and the fresh food fan are all axial fans.
 4. The refrigerator appliance of claim 1, wherein the convertible chamber and the freezer chamber are separated by a removable slide-in mullion.
 5. The refrigerator appliance of claim 4, wherein the mullion is surrounded by insulating foam to fix the mullion in place.
 6. The refrigerator appliance of claim 1, wherein the fresh food supply duct, the convertible chamber supply duct, and the convertible chamber return duct are all positioned between the inner liner and a rear wall of the cabinet.
 7. The refrigerator appliance of claim 1, further comprising: a vacuum insulated panel positioned on an opposite side of the fresh food supply duct, the convertible chamber supply duct, and the convertible chamber return duct relative to the inner liner.
 8. The refrigerator appliance of claim 1, wherein the fresh food supply duct comprises a flow restriction for restricting a flow of cooled air that passes through fresh food supply duct.
 9. The refrigerator appliance of claim 1, wherein the convertible chamber supply duct defines a convertible chamber inlet and the convertible chamber return duct defines a convertible chamber outlet positioned adjacent the convertible chamber inlet along the lateral direction, and wherein the dual damper comprises a single damper flap that simultaneously opens or closes the convertible chamber outlet and the convertible chamber inlet.
 10. The refrigerator appliance of claim 1, wherein the dual damper comprises a single drive mechanism for moving the dual damper between the open position and the closed position.
 11. The refrigerator appliance of claim 1, wherein the evaporator chamber is positioned within the freezer chamber of the refrigerator appliance.
 12. The refrigerator appliance of claim 1, wherein the fresh food chamber is positioned above the convertible chamber along the vertical direction and the convertible chamber is positioned above the freezer chamber along the vertical direction.
 13. The refrigerator appliance of claim 1, further comprising: a first fresh food return duct and a second fresh food return duct positioned on opposite sides of the fresh food chamber along the lateral direction, the first fresh food return duct and the second fresh food return duct extending between the fresh food chamber and a suction side of the evaporator chamber substantially along the vertical direction.
 14. A duct system for a refrigerator appliance, the refrigerator appliance comprising a cabinet containing an inner liner defining a fresh food chamber, a convertible chamber, a freezer chamber, and an evaporator chamber, the duct system comprising: a fresh food supply duct providing fluid communication between the evaporator chamber and the fresh food chamber; a convertible chamber supply duct providing fluid communication between the evaporator chamber and the convertible chamber; a convertible chamber return duct providing fluid communication between the convertible chamber and the evaporator chamber; and a dual damper operably coupled to the convertible chamber supply duct and the convertible chamber return duct, the dual damper being configured for selectively and simultaneously opening or closing the convertible chamber supply duct and the convertible chamber return duct.
 15. The duct system of claim 14, further comprising: a freezer fan for urging a flow of cooled air from the evaporator chamber into the freezer chamber; a convertible chamber fan for urging a flow of cooled air from the evaporator chamber into the convertible chamber when the dual damper is open; and a fresh food fan for urging a flow of cooled air from the evaporator chamber into the fresh food chamber.
 16. The duct system of claim 15, wherein the freezer fan, the convertible chamber fan, and the fresh food fan are all axial fans.
 17. The duct system of claim 14, wherein the fresh food supply duct, the convertible chamber supply duct, and the convertible chamber return duct are all positioned between the inner liner and a rear wall of the cabinet.
 18. The duct system of claim 14, further comprising: a vacuum insulated panel positioned on an opposite side of the fresh food supply duct, the convertible chamber supply duct, and the convertible chamber return duct relative to the inner liner.
 19. The duct system of claim 14, wherein the fresh food supply duct comprises a flow restriction for restricting a flow of cooled air that passes through fresh food supply duct.
 20. The duct system of claim 14, wherein the convertible chamber supply duct defines a convertible chamber inlet and the convertible chamber return duct defines a convertible chamber outlet positioned adjacent the convertible chamber inlet along the lateral direction, and wherein the dual damper comprises a single drive mechanism for moving a single damper flap that simultaneously opens or closes the convertible chamber outlet and the convertible chamber inlet. 